Heat exchanger



July 22,1947- J. w. BROWN, .l

HEAT EXCHANGER Filed Sept. 4',v 1944 4 INVENTOR. J'hN W BEOV/V/V 1. J7E

A TTDEWEYS l Patented July 22, 1947 HEAT EXCHANGER John W. Brown, Jr., Lakewood, Ohio, assigl'nor to Brown Fintube Company, Elyria,l Ohio, a

corporationof Ohio Application September 4, 1944, Serial No. 552,633

Claims. l

This invention relates to tubular connections and more particularly to connections or fittings for joining two tubes or pipes of different diameters. The connections or fittings are especially useful in heat exchangers, but it is to be understood that they may be employed for other purposes. I

A general object of the invention is to provide an eilcient connection for joining tubes of diierent diameters, which can be manufactured at relatively low cost and which will withstand extremely high pressures without leakage. Another object is to provide such a connection which readily can be assembled or disassembled without requiring any special tools or equipment. Another object is to provide such a connection, particularly for concentric tubes, in which no substantial torsional forces are placed on either the inner tube or the outer tube by the operations of connecting and disconnecting the connection. A further'object is to provide an efiicient and economical heat exchanger embodying such a tubular connection.

Further objects and advantages of the invention will become apparent from the following description of a preferred form thereof, reference being made to the accompanying drawings in which Figure 1 is an elevation partly in section showing a double tube heat exchanger made according to my invention; Figure 2 is a front elevation of the heat exchanger shown in Figure 1; Figure 3 is a rear elevation with parts broken away, showing the heat exchanger of Figure l; and Figure 4 is an enlarged cross sectional detail showing the construction of the connection between the inner and outer tubes oi' the heat exchanger.

In the drawings I have illustrated a heat exchanger designed to employ my preferred form of tubular connection. This heat exchanger is of the hairpin type and comprises an inner hairpin or U-tube indicated generally at I Il and made up of two straight portions Ii and I2 connected by a return bend I3, preferably welded to the straight portions as indicated at It, although unions or other means for connecting the return bend and the straight portions may be .employed if desired. Shell tubes I5 and I6 surround the straight portions II and I2 of the hairpin tube i. In order to increase the rate of interchange of heat between the commodity within the tubes II and I2 andy the commodity surrounding these tubes and within the shell tubes I5 and I 6, the straight portions II and I2 are preferably provided with fins I'l construct- PatentsNos. 2,261,136 and 2,261,137.`

ed in accordance with the teachings of The tubes I I and I2 are provided at their outer or exposed ends with fittings or unions I8 and I9 to which inlet and outlet pipes I9 and 20 may be secured as by the coupling nuts 2I and 22.I

If the exchanger is designed for counterfiow operation the other commodity may be supplied to the interior of the shell tube I6 through the inlet pipe 25 welded to the shell tube as shown at 26 and provided at its end with a conventional flanged connection as at 21. Fluid ksupplied through the inlet 25 flows in the direction of the arrows to the rear end of the exchanger where the tube I6 is conected to the tube I5 by means of plates 28 welded to the exterior of the tubes as indicated at 29 and 30, and plate 3|, welded to the tubesiand to the plates 28, the walls of the tubes I5 and I6 being cut away to provide a fluid passage between the plates 28 andY to provide space for the return bend I3 as shown in Figure 3. A removable cover plate 35 is secured by bolts 36 to the ilange 31 which is welded to the ends of the tubes i5 and I 6 and the plates 28. One of the bolts, indicated at 36a, is preferably elongated as shown, thus providing a pivotal support whereby the cover piate can be pulled out of engagement with the other bolts, and then swung about the bolt 36a as a pivot to give access to the interior of the exchanger. The cover plate may be secured in displaced position by one of the bolts 36 adjacent bolt 36a.

A suitable gasket 38 may be provided between the coverplate and the flange in order to make a leak-proof connection. Thus uid may flow to the rear of the heat exchanger through the tube I6 around the outside of the return bend I3 and into the tube I5, thence within the tube I5 to the outlet pipe 39 which, like the inlet pipe 25, is provided with a conventional flanged union 4U. With such an arrangement, counterow of the commodities in the inner and outer tubes will take place. If desired, concurrent ow may be obtained merely by reversing the inlet and outlet connections for either the inner tube or the outer tubes. Several exchangers may be connected together in series in the usual manner if desired, and may be supported by' brackets 4I my `prior 3 hairpin tube must be leakproof under high pressures and widely varying temperature conditions. must accurately position the tubes with respect, to each other, and must be designed so that it can be assembled and demounted without difliculty.l These and other advantageous results I attain by 'providing a fitting or connection, the principal parts of which comprise a bushing or sleeve member 45 welded or otherwise suitably secured to the exterior of the hairpin tube Il near one end thereof, a split elamping ring 45 which engages the bushing 45 and a flange 41 'on the shell tube I5 and a' sealing ring 48. The fitting for the leg Il of the hairpin tube is described herein. .The fitting for the leg i2 is preferably identical therewith.

'I'he clamping ring 46 which, as shown in Figure 2, is composed of two halves indicated at 44a and 46h, has an inwardly extending flange Il which is undercut asat I to engage the correspondingly undercut surface 52 of thefiange 41. At its other end, the clamping ring 44 is provided with another inwardly extending fiange 55 vwhich is threaded to receive the cap screws 54 and which projects into the'annular recess II of the bushing 45. The recess 55 terminatesin an undercut shoulder 56 and the portion 51 of the flange 53 projects outwardly toward the end o! the tube Il to conform to the undercutshoulder'li. By this arrangement the split ring 4l is firmly held in position on the exchanger so long as there is any strain on the parta'butmay be readily re moved as soon as the cap screws 54 are loosened slightly.

The engagement of the split ring 45 with the undercut shoulder 56 of the brushing 45 accurately positions the bushings and the inner tube with respect to the shell tube. Thus, when the cap screws 54 are tightened against the sealing ring 48 the ring is urged toward the radial surfaces 60 and 6I of the flange 41 and bushing 45 respectively, compressing the gasket 52 and creating a seal between the inner and outer tubes. The engagement between the clamping ring 46 and the shoulder 5B holds the bushing and inner tube against the sealing pressure exerted by the sealing ring 48 on the gasket 52 and shoulder 6i. Also this same engagement between the inwardly extending flange 55 and the shoulder 56 supports the inner periphery of the flange 53 and balances the outboard stresses which would otherwise occur in the flange 53 when the cap screws were tightened to seal the joint. The parts are so proportioned that when the sealing ring is in position with the inwardly extending flanges engaging the undercut shoulders 52 and 56, the radial sealing rtubes by swinging the cover plate 35 to one side,

using the bolt 34a as a pivot, disconnecting the coupling nuts 2i and -22 from the fittings Il and I9, and breaking the connection between the inner and outer tubes in the manner described above. Then the hair pin tube can be pulled out of the'two U-tubes through the opening at the rear of the exchanger made by removing the cover plate 35. In exchangers wherein the return bend of the hairpin tube is connected to the straight portions thereof by couplings or unions. then the straight portions of the hairpin time can be separately removed from the shell tubes by disconnecting them from the return bend, breaking the connection between the shell tubes and the straight portions as described above and pulling the tubes outwardly from the front end of the exchanger. i. e., to the right inthe drawing. Thus my fitting or connection is adapted to heat exchangers of various types as well as being useful in other environments where it is desired to Conneet tubes or pipes of different diameters.

As explained above, -my fittings may be tightened or loosened merely by tightening or loosening the relatively small cap screws 54. The elimination of large nuts and unions makes possible a compact construction and greatly increases the ease of assembly and demounting. Only small Vwrenches are required for the cap screws I4.

Thus no severe torsional strains or stresses can.

be placed on either the shell tube or the fin time in the operation of tightening the joint, nor is either tube placed under compression or tension in making the joint. The hairpin tube is held fixedly in proper position with respect to the shell tubes by the ccmnection, yet the tube is free to expand and contract under the influence of temperature changes without placing any strain upon the connection. 'I'he gasket can be replaced readily'when necessary and the sealing surfaces 4 can be inspected and cleaned immediately before surfaces and 6| lie in substantially the same l plane so that the gasket 62 when compressed by the sealing ring 48 exerts substantially equal pressures on both surfaces.

As noted above ythe connection can be disassembled merely by loosening the cap screws 54 a few turns. As soon as the cap screws are loosened sufflciently to permit the two halves 46a and 45h of the clamping ring 46 to be disengaged from the undercut shoulders 52 and '55, the halves of the clamping ring can be removed bodily .from the assembly. Then the inner tube il can be moved in either direction with respect to the outer tube I5 and thesealing ring 48 and gasket 62 can be slipped off of the bushing 45, thus completely breaking the joint.

In the particular heat exchanger shown the hairpin tube can be removed from the @W0 Shell the gasket and sealing ring are placed in position. The parts are shaped so that they can be formed and machined at relatively low cost and with ordinary production methods.

Those skilled in the art will appreciate that various changes and modifications can be made in my invention without departing from the spirit or scope thereof. It is therefore to be understood that my patent is not limited to the preferred form of my invention described herein, or. in any manner other. than by the appended claims.

I claim:

1. In a heat exchanger embodying an outer tube and an inner tube concentric therewith. means for connecting the inner tube to the outer tube comprising means providing a sealing surface adjacent one end of the outer tube, a fitting on said inner tube, said fitting having a sealing surface facing in the same direction as the sealing surface adjacent the end.of the outer tube, said fitting also providing a shoulder opposed to the sealing surface thereon, a locking ring engaging said outer tube and having an inwardly extending flange engaging said shoulder of said fitting, a sealing ring disposed within said locking ring and adapted to seal against said sealing surfaces of said outer tube and said fitting, and means carried by said locking ring for vurging said sealing ring into sealing engagement with said sealing surfaces.

. 2. In al heat exchanger embodying an outer WDC? and an inner tube concentric therewith.

means for connecting the outer surface ofI the inner tube to the inner surface of the outer tube comprising an exterior flange at one end of the outer tube. said flange having an'outer sealing surface, a fitting on said inner tube, said fitting having an' annular sealing surface disposed within and substantially in the same plane as said outer sealing surface, said fitting also providing an annular shoulder of lesser diameter than and opposed to said annular sealing surface and disposed beyond the end of the outer tube, a split locking ring having a flange engaging the inner surface of said exterior flange and a second flange engaging said annular shoulder of said fitting, a sealing ring, having an internal diameter greater than the external diameter of said shoulder, disposed within 'said split locking ring and adapted to seal against said sealing surfaces of said flange and said fitting, and means carried by said second flange of said split locking ring for urging said sealing ring into sealing engagement with said flange and said shoulder.

3. In a heat exchanger embodying an outer tube and an inner tube concentric therewith, means for connecting the inner tube to the outer tube comprising an exterior flange at one end of the outer tube, said flange having a plane outer surface and an undercut inner surface, a fitting on said inner tube, said fitting having a cylindrical portion fitting within the outer. tube and terminating in a radial shoulder disposed in substantially the same plane as the outer surface of said flange, said fitting also providing an undercut annular shoulder of lesser diameter than and opposed to said first mentioned shoulder and disposed beyond the end of the outer tube, a split locking ring having a flange engaging the -`underout inner surface of said exterior flange and a second flange engaging said undercut annular shoulder of said iltting, a continuous sealing ring, having an internal diameter greater than the externai diameter of said annular shoulder, disposed within said split locking ring and adapted to seal against the plane outer surface of said outer tube flange and the radial shoulder of said fitting, and a plurality of screws threaded in said second flange of said split locking ring for urging said sealing ring into sealing engagement with said flange and said shoulder.

4. In a heat exchanger embodying an inner hairpin tube, and outer tubes surrounding each leg of the hairpin tube, means for providing a leak-proof connection between the outer surface of each leg of the inner tube and the inner surface of the associated outer tube, each such means comprising an exterior flange at one end of the outer tube, said flange having a plane outer surface and an undercut inner surface, a fitting on said inner tube, said iltting having a cylindrical portion fitting within the outer tube and terminating in a radial shoulder facing in the same direction as the outer surface of said flange, said fitting also providing an undercut annular shoulder of lesser diameter than and opposed to said first mentioned shoulder and disposed beyond the end of the outer tube, a split locking ring having a flange engaging the undercut inner surface of said exterior flange and a second flange engaging said .undercut annular shoulder of said fitting, a sealing ring disposed within saidvsplit locking ring and adapted to seal against the plane outer surface of said outer tube flange and the radial shoulder of said fitting, and a plurality of screws threaded in said second flange of said split locking ring for urging said sealing ring into sealing engagement with said flange and said shoulden 5. In a heat exchanger embodying an outer tube and an inner tube, means for forming a iluid tight connection between the inner tube and the outer tube comprising an outwardly facing shoulder on the outer tube, a shoulder on the inner tube facing in the same direction and disposed in substantially the same plane as the shoulder of the outer tube, said shoulders providing adjacent sealing surfaces one within the other, a seal- Aing ring overlying both of said sealing surfaces at least in part, and clamping means for urging said sealing ring into sealing engagement with both said surfaces, said clamping means being anchored against the reaction of the pressure of said sealing ring against said sealing surfaces by engagement with both said outer tube and said inner tube. A

6. In a heat exchanger embodying an outer tube and an inner tube, means for forming a fluid tight connection between the inner tube and the outer tube comprising an outwardly facing shoulder onthe outer tube, a shoulder on the inner tube facing in the same direction and disposed in substantially the same plane as the shoulder of the outer tube, said shoulder providing adjacent sealing surfaces one within the other, a sealing ring overlying both of said shoulders at least in part, a split locking ring, and screw means carried by said locking ring for urging said sealing ring into sealing engagement with both said surfaces, said locking ring being anchored against the reaction of the pressure of said sealing ring against said sealing surfaces by engagement with both said outer tube and said inner tube and reacting against both said tubes in the same direction.

7. A tubular connection for forming a fluid tight connection between an inner tube and an outer tube, comprising an outwardly facing shoulder on the outer tube, a shoulder on the inner tube facing in the same direction as the shoulder of the outer tube, said shoulder providing adjacent sealing surfaces one within the other, and means for sealing against -both said shoulders comprising a sealing ring overlying both of said shoulders at least in part and clamping means for urging said sealing ring into sealing engagement with both said surfaces, said clamping means being anchored against the reaction of the pressure of said sealing ring against said sealing surfaces by engagement with both said cuter tube and said inner tube.

8. A tubular connection for forming a leakproof connection between an inner tube and an outer tube and for positioning said tubes with respect to each other, said connection comprising means providing a sealing surface adjacent one end ofthe outer tube, a fitting on said inner tube, said tting having a sealing surface facing in the same direction as the sealing surface adjacent the end of the outer tube, said fitting also providing a shoulder opposed to the sealing surface thereon, a locking ring engaging said outer tube and having an inwardly extending flange engaging said shoulder of said tting, a sealing ring disposed within said locking ring and adapted to seal against said sealing surfaces of said outer tube and said tting, and means carried by said locking ring for urging said sealing ring into sealing en` gagement with said sealing surfaces.

9. A tubular connection for connecting Aconcentric inner and outer tubes comprising an eX- terior flangel at one end of the outer tube, said ilange having an outer sealing surface. a-iltting on said inner tube, said fitting having an annular i engaging the inner surface of said exterior ange l and a second flange engaging said annular shoulder of said fitting, a sealing ring disposed within said split locking' ring and adapted to seal against said sealing surfaces of said flange and said f1tting, and means carried by said second ilange of said split locking ring for urging said sealing ring into sealing engagement with said ange and said shoulder.

10. A tubular connection for connecting two tubular members of different diameters comprising an exterior flange at one end of the larger tubular member, said flange having a, plane outer surface and an undercut inner surface, a tting on the smaller member, said fitting having a cylindrical portion fitting within the outer member and terminating in a. radial shoulder disposed in A25 of said flange, said iitting also providing an undercut annular shoulder of lesser diameter than i and opposed to said first mentioned shoulder and disposed beyond the end of the outer tube', a, split locking ring having a flange engaging the undercut inner surface of said exterior flange and a second flange engaging said u ndercut annular shoulder of said fitting, a sealing ring disposed within said split locking ring and adapted to seal against the plane outer surface of said outer tube flange and the radial shoulder of said fittingI and a plurality of screws threaded in said second flange of said split locking ring for urging said sealing ring into sealing engagement with said flange and said shoulder.

JOHN W. BROWN, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date McWane June l2, 1934 Goosman Oct. 2l, 1924 Leman Aug, 20, 1935 Number 

